LeetCode in Kotlin

991. Broken Calculator

Medium

There is a broken calculator that has the integer startValue on its display initially. In one operation, you can:

• multiply the number on display by 2, or
• subtract 1 from the number on display.

Given two integers startValue and target, return the minimum number of operations needed to display target on the calculator.

Example 1:

Input: startValue = 2, target = 3

Output: 2

Explanation: Use double operation and then decrement operation {2 -> 4 -> 3}.

Example 2:

Input: startValue = 5, target = 8

Output: 2

Explanation: Use decrement and then double {5 -> 4 -> 8}.

Example 3:

Input: startValue = 3, target = 10

Output: 3

Explanation: Use double, decrement and double {3 -> 6 -> 5 -> 10}.

Constraints:

• 1 <= startValue, target <= 109

Solution

@Suppress("NAME_SHADOWING")
class Solution {
    fun brokenCalc(startValue: Int, target: Int): Int {
        var target = target
        var result = 0
        while (startValue != target) {
            if (target > startValue && target % 2 != 0) {
                target += 1
                result++
            } else if (target > startValue) {
                target /= 2
                result++
            } else {
                result += startValue - target
                break
            }
        }
        return result
    }
}

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